Ashura is a major Shi'a muslim holiday. Shi'a commemorate the martyrdom of Husayn ibn Ali (Imam Hussein), the grandson of Muhammad at the Battle of Karbala on the 10th of Muharram (Abt. October 10th). Muslims use a lunar calendar so the date varies slightly each year on the Gregorian calendar. Ashura is a day of rememberance, mourning and fasting for all martyrs and also an observance of Jihad which is considered a 6th pillar of Islam faith.
Ashura can also observed by Sunni muslims who commemorate God's deliverance of Israel. Sunni's believe that Moses fasted on this day in thanksgiving for Allah's parting the Red Sea.
There is considerable variation in observance of Ashura among different Shi'a and Sunni communities. Generally, it is a day of mourning, introspection, and fasting. Many muslims may choose to not listen to music that day. Shi'a muslims in Iraq, Iran, Pakistan, may participate in cutting of the forehead, blood-letting and bloody self-flagellation. Observers wear white clothing which is stained red with their blood. Some muslim clerics prohibit blood-letting, while others encourage blood donation to the Red Cresent Society.
The reasons for blood letting and self-flagellation varies. Generally, it can be viewed as a commemoration and penance for the Battle of Karbala and other religious battles. It can be a recommitment of muslims to devote their life to follow God and overcome the weakness of the flesh. It is also believed that observance of Ashura produces a forgiveness of sin.
Ritual self-flagellation is not unique to Muslims. Some Catholic monastic orders and members of Opus Dei practice self-flaggelation. Processioners during the Passion of Christ in the Philippines, Mexico, and Peru may also participate in self-flaggelate and blood-letting as they reinact Christ's suffering leading up to His crucifixion. These practices were dramatized by the character Silas in "The DaVinci Code". Practicioners of self-flaggelation feel that they can be closer to God as they join in with Christ in His suffering.
Latter-day Saints do not recognize or practice "blood atonement". Only the blood of Christ forgives sin. Christ was the great and last blood sacrifice. The shedding of blood of any other human, or animal or even our own blood cannot expiate or atone for our sins. True Christan's accept the blood sacrifice of Jesus Christ by receiving the ordinance of baptism and participation in and partaking of the Lord's Supper or sacrament each week.
Brigham Young mentioned the idea of what some call "blood atonement" in a only a few of his myriad discourses. It is my opinion that Brigham Young was teaching about the process of receiving a hope of forgiveness for what the Book of Mormon calls the "unpardonable sin". This is not some mystical doctrine but just the proper application of the steps of repentance for very serious sins.
Some people like Sherem in the Book of Mormon and the malifactor crucified next to Christ considered their sins so terrible that they were unpardonable and beyond the reach and power of Christ's atonement. This isn't "death-bed" repentance but about a man who finally came to himself, confessed his sin, accepted his punishment, accepted and defended Christ against the accusations of the other malafactor who said "if thou be the Christ, save thyself and us". Christ told the penitent thief, "To day shalt thou be with me in paradise."
Many people involved in dark conspiracies wish they could escape but continue to go along with the false promise that they will escape judgement and that they could not possibly be forgiven anyways. Conspiracies prevent infiltration from spies by requiring members to commit terrible acts involving murder and pedophilia to enter the inner circles and upper echelons.
However, scripture teaches that forgiveness may be possible through the atonement of Christ by 1. accepting Jesus Christ 2. full public confession 3. voluntarily accepting required punishment for sin. Conspiracy loves to send false defectors and so-called insiders who come over from the bad side to the good side. However, if they really were an insider, the sins they would be confessing to would likely require capital punishment, or being placed in a public online database and imprisonment. But the way the good side could tell that a defector had truely repented would be that they made a full confession, and accepted the full consequences of their sins with no appeals or plea-deals. Their voluntary acceptance of punishment would seal the truth of their public confession.
I don't think there is necessarily any requirement to having your blood ritually shed on the ground. This has been given as a reason death by firing squad is preserved as an approved method of execution in Utah. In my opinion this is just a veiled way to link the false doctrine of blood atonement with LDS theology.
While unspeakable atrocities are required by evil so insiders can know who they can trust, the Holy Temple works in a similar but opposite manner. Joseph Smith had a difficult time in Kirtland knowing who he could trust. The righteous requirements of the Holy Temple reveal to God's people who they can trust and prevent infiltration. The wicked cannot bare the righteous requirements of the Holy Temple just like any righteous person could not bare the wicked requirements of evil (spirit cooking, and worse, etc).
God talked about this in D&C 101 about the consequences of the Saints not building a temple in Missouri and not being able to "see the enemy afar off". Enemies of the church joined and like moles formed the secret society called "Danites" who fomented animosity between the Saints and neighbors. Judaism and the US without the Holy Temple have similarlly been infiltated by evil individuals who have committed great atrocities in their name. The function and righteous requirements of the Holy Temple reveals to us who we can trust to lead us.
What positive can we learn from Ashura and the ancient amd modern practice of self-flagellation? Christ's atonement represented the great and last blood sacrifuce. God will no longer accept sacrifice by the shedding of blood of any animal. The God wanted all along was a sacrifice of a broken heart and a contrite spirit. Even though the Law of Moses is fulfilled, and true followers of God no longer practice animal sacrifice, the Law of Self-sacrifice itself is still very much a thing and can bring us closer to Christ.
Instead of pondering on and calculating how much blood you can lose without passing out, I prefer to think of ways I can sacrifice my time, talents, and resources to peaceably build God's kingdom on the Earth and serve others. And although we are counseled to not run faster than we have strength, I believe sacrifices should stretch us, make us a bit uncomfortable, and even hurt a little. Self-sacrifice in this way can bring us closer to God and Christ and can result in the spiritual strength to repent of, forsake and be forgiven of sin. However, we cannot continue in sin, and think giving charity or service alone (indulgences) without true repentance will hide our sins.
"And above all things have fervent charity among yourselves: for charity shall cover the multitude of sins." (1 Peter 4:8)